These studies, plus our findings that chronic hyperleptinemia leads to hypertension in pregnant rats and increases TNF-α levels in their placentas, which occurred independently of leptin-induced reductions in food intake as determined by food-restricting normal pregnant rats to match the food intake of those receiving leptin (Figure 5) [66], point to leptin as a link between obesity and PE. This evidence concerns the gene TNF and obesity due to melanocortin 4 receptor deficiency.